download mushclient. make two worlds, one called "arctic one", the other "arctic two".
go to world settings, go to scripts. turn the script type to VB Basic.
create aliases. the simplest is z *, to output this:
set otherworld = world.getworld ("arctic two")
if not (otherworld is nothing) then
otherworld.send "%1"
set otherworld = nothing
end if
turn the "send to" dropdown box to "script" in the alias. now in your main window, just type "z rest", and the other window will rest. now you play with one window, but in split screen. make sure to turn the output to script in the alias though or it won't work.
you can also set real aliases. i.e. in my thief window, i have an alias for "rit" to send "cast 'ritual voyage' thief" to my shaman, i generally on tank types use "qq" for assist, bite, swarm, then trigger instinct outputs to bite/swarm again... you can pretty easily create a ghetto setup that will make your life a lot easier